<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        function sum() {
            var total = 0
            for (var i = 0; i <= 100; i++) {
                if (i % 2 !== 0) {
                    total += i
                }
            }
            return total
        }
        console.log(sum());
    </script>

    <script>
        let timer = null
        window.addEventListener("scroll", function() {
            if (timer) {
                clearTimeout(timer)
            }
            timer = setTimerout(() => {
                console.log("动了");
            }, 200)
        })
    </script>
</body>

</html>